Variable pitch propeller control



April 14, 1942. COLLEY ETAL 2,279,301

VARIABLE PITCH PROPELLER CONTROL Filed Sept. 28, 1938 INVENTOR JOHN HAYS HAMMOND, JR.

BY GEORGE A.COLLEY.

[Patented Apr. 14, 1942 VARIABLE PITCH PROPELLER CONTROL George A. Colley, Newton Centre, and John Bays Hammond, Jr.. Gloucester, Mass: said Oolley assignor to said Hammond, Jr.

Application September 28, 1938, Serial No. 232,048

7 Claims.

This invention relates to variable pitch propellers and more specifically to means for varying the pitch of a propeller so as to maintain the thrust of the'propeller constant under varying conditions of wind and weather.

The invention provides thrust indicating means, operated by a thrust meter which directly controls means for varying the pitch of the propeller blades in such a way as to maintain the propeller thrust constant.

The invention also provides means icr varying the rate of change of pitch of the propeller blades "in accordance with the rate of change of the propeller thrust, thus preventing rapid changes of pitch which might cause unnecessary strain and vibratlon nn the driving machinery.

The invention also sconsists in certain new and ::original 'teaturess}! construction and combina- 1101151 pause-hereinafter set forth and claimed. Althbughthe nova-gestures which are believed l this invention will be particularly pnintedsmtitiiin the claims appended :=hereto,:3$1e; ?inv" itseli'. as to its objects s'qa'ndeadvantags fiifiipde of its operation and ethe =mannr iif-fits wanization may be better .i to the following descripn with the accompanypart thereof, in which T the. slngieiiigure illustrates diagrammatically the 3systcrn as ;'appliedto the driving mechanism ota marine-weasel.

In the allowing description and in the claims parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring to the accompanying drawing, the hull of a marine vessel is indicated at II. This vessel isadriven lay-means of a propeller l2 which 'ded-witnadiustab1e blades It. The pro- 't theesd of a hollow shaft 1 not-shdwmior maintaining a constant Dm fimtlen, Y a connected to a variable pitch 1 ,air be of any well known "ad ction suchas that menu viadtucedby :"theyjilscheii-wvss Company of zuriom swltzerlandfithe detail$ of which form no part ckthe invention and are acccrdinglymot-suwifl imy set forth herein. This mechanism, ingeneha lrcomprises a red I 8 slidable longitudinally within the shaft i5 and connected to control the pitch of the blades II. The rod I9 is actuated by a piston 21 in a fluid pressure cylinder 21a. Fluid for actuating the piston 21 is supplied by a pump 26 through a control valve and a distribution valve 250 which communicates with the cylinder 210 through ducts, not shown, in the shaft 15. A motor 2| rotates a worm 22 which operates to move the upper end of a floating lever 23, which, in turn, is pivoted to the end of a valve rod 24 which controls the valve 25. The piston 21 is connected by a rod 28 to a collar 29 which is slidably mounted on the shaft l5 and engages the lower end or the lever 23 so that the position of this end of the lever corresponds to the pitch of the blades II.

The upper end of the lever 23 is connected by a wire 30 to an indicatoril which shows the pitch at which the blades liareset. Stops 32 are provided for limiting the maximum and minimum pitch of the blades-i3. The fluid pump 26 is driven either by a 1110151315330! a belt 35 from thegshait IS. A reservoir =36 rand a supply tank 3i are provlded for the necessary fluid.

It is to be understood that other pitch control devices may be employed in-place of that referred to *abov'e, for varying the pitch of the propeller blades l3 in response to actuation of the motor 2|. A particular type is shown for purposes of illustration only.

The thrust bearing ll is also of standard construction and only so much thereof has been shown as is necessary to an understanding of this invention. In the form shown the thrust bearing is provided with the usual collar 00 and shoe ll which is engaged by thrust pins '42, which, in turn, cooperate with piston pins 43, the outer ends of which are engaged by pistons which reciprocatein cylinders 46. Mounted on the cylinders 46 are gauges 41 which indicate the travel of the pistons 65. Fluid under pressure for operating the system is supplied by a manually operated pump 48 which is connected by piping G9 to the-cylinders and-to a damping valve 80. This valve is connected by a pipe 5| to an indicator 52 which is provided with a pointer 53 which registers with a scale 54 which may be graduated in thousands of pounds thrust.

While the thrust bearing and meter shown is the type manufactured by the Kingsbury Machine Works of Philadelphia, Pennsylvania, it is to be understood that any other suitable type'oi' thrust bearing'and meter may be employed for the purpose.

In accordance with the present invention, means is provided for controlling the motor II by the position or the pointer 08. In the embodiment shown, this is accomplished by providing a contact ll, attached to, but insulated from. the pointer 03 and a ring I! surrounding the indicator II and rotatably mounted thereon. The ring 01 carries a segment of a worm gear ll. Meshing with the gear 68 is a worm is which may be rotated by means of a knurled knob l0. Mounted on but insulated from the ring 41 are a plurality of contact segments II to 08 which are selectively engaged by the contact 58.

The segments Ii and 60 are connected by flexible conductors to two conductors l and H which in turn are connected to the reversing windings oi the motor H. The segments '2 and 03 are connected by flexible conductors to two resistors I8 and 11 the other ends oi which are connected to the conductor 10. The segments 64 and are connected by flexible conductors to two resistors 00 and BI the other sides oi which are connected to the conductor II. The return lead from the windings of motor 2| is connected to one side of a battery 82 the other side of which is connected to the blade of a three position switch 03. The center contact of this switch is connected to the contact 58, the upper contact is connected to the conductor Ii and the lower contact is connected to the conductor I0.

Operation In the operation of the form of the invention shown, the pitch of the blades I3 is set at the normal operating angle for the conditions under which it is desired to operate the vessel. The setting of the propeller blades i3 is accomplished by moving the blade of the switch 83 into the upper or lower position which will cause the motor It to move the upper end of the lever 28 to the left or right to increase or decrease the pitch in a well known manner, the angle of pitch being indicated by the pointer of the indicator 3i.

The vessel is then brought up to the desired speed and the pump ll is manually operated to build up hydraulic pressure in the system, this pressure being indicated by the pointer 53 on the scale 5|. After the pressure has been built up sufllciently behind the pistons 45 it will exert enough pressure through the piston pins 0 and thrust pins 42 to take the entire thrust oi the propeller l2. When this condition has been reached, as indicated by the gauges 41, the manual operation of the pump 40 is stopped. The

gages the contact 56. The Blade of the switch I! is then moved into engagement with the center contact.

If the conditions under which the vessel is travelling should change, such as encountering a;

a strong head wind or running into a heavy sea and the thrust be thereby increased, the piston will receive more pressure so that the hydraulic cylinder 46 will transmit more pressure to the indicator I2 the pointer I of which will therefore rotate in a counter clockwise direction to indicate an increase oi thrust. The contact It will then engage the segment 03 and a circuit will be closed from the battery I! through the slowly in a direction to move the upper end of the lever 13 to the right. This will 'move the valve II to the right which will allow fluid under pressure to pass from the pump 20 to the cylinder 21a by means of the ducts in the shaft II. This will actuate the piston 21 which, by means of the rod II and the link mechanism will cause the propeller blades II to slowly decrease their pitch, thereby decreasing the thrust until it reachs 5000 lbs. at which time the contact 50 will again rest on the insulation between segments II and I thus stopping the motor 1|.

Ii the thrust should decrease dueto a following wind or other favorable conditions, the reverse action would take place, thus causing a gradual increase in pitch of the propeller which would cause the thrust to be increased until the contact 58 again rests on the insulation between the segments BI and 64, at which time the motor 2| would stop.

Ii the changed conditions cause a rapid change of thrust so that the contact 68 engages either segment or segment 62, then the resistor 8! or 10 will be thrown in circuit with the motor 2! instead of the resistor or ll as already described. As resistors BI and I6 have less resistance than resistors 80 and 11 the motor II will be caused to rotate faster, thus changing the propeller pitch more rapidly to take care of the more rapidly changing conditions.

If the conditions change so quickly that the contact 58 engages either segment Si or segment It, then no resistance will be thrown in the circuit of the motor II and it will rotate at its maximum speed, thus changing the propeller pitch at a maximum rate. The stops 3! are provided so that the propeller pitch is prevented from exceeding certain limits beyond which it :iould not operate eihciently under any condions.

In this way the pitch of the propeller blades I3 is varied to cause the propeller to operate so as to maintain the thrust constant under all conditions. The rate of change of pitch will vary in accordance with the change of thrust so that with a gradual change of thrust there will be a slow change oi propeller pitch thus preventing violent changes of pitch which would cause undue strain on the driving mechanism, disagreeable vibrations and inefliciency oi the propeller.

The pitch has been shown herein as controlled by thrust. Other conditions, such as speed, depth, fuel consumption, motor speed, motor e1- flciency, etc., may also be used to control the propeller pitch so as to maintain any desired operating conditions. In the case of aircraft, control may also be responsive to speed. air density, load, angle of flight or any other variable condition encountered in flight.

Although only a few oi the various forms in which this invention may be embodied have been shown herein, it is to be understood that the invention is not limited to any specific construction but may be embodied in various forms without departing from the spirit 0! the invention or the scope of the appended claims.

What is claimed is:

having blades, means controlling the pitch' of said blades, a thrust bearing for said propeller, means responsive to changes in thrust applied at said bearing, and means actuating said control means in response to changes in said thrust reresistor 11 to the motor 2| causing it to rot te 78 sFonsive means so as to vary the pitch of said badgs in a manner to maintain said thrust cons an 2. The system set forth in claim 1 in which the thrust responsive means comprises a fluid pressure means opposing the thrust, whereby changes in thrust cause variations in the fluid pressure, and an indicator actuated by said changes in fluid pressure.

3. In a system for driving a vessel, a propeller having blades, means controlling the pitch of said blades, a thrust bearing for said propeller, fluid pressure means opposing the thrust in said bearing whereby changes in thrust cause variations in the fluid pressure, an indicator actuated by said changes in fluid pressure, a control circult for actuating said pitch control means and means associated with said indicator to energize said control circuit whereby the pitch is varied in accordance with the thrust and in a manner to maintain the thrust constant.

4. The system set forth in claim 3 in which the propeller is driven at a constant speed.

5. The system set forth in claim 3 in which the speed of operation of the control circuit is varied in accordance with the amplitude of deflection of said indicator.

6. The system set forth in claim 3 in which the indicator is provided with a plurality of contacts which are adapted to be selectively closed in accordance with the position thereof and control circuits are associated with said contacts to actuate said pitch control means in a direction determined by the direction of deflection of said indicator and at a speed determined by the amplitude of such deflection.

7. In a system for driving a vessel, a propeller having blades, means controlling the pitch of said blades, means directly responsive to both the di rection and amount of change of thrust of said propeller. and means actuated by said thrust-responsive means to actuate said pitch controlling means to change the pitch of said blades in a direction to maintain the thrust constant and at a speed proportional to the amount of change in thrust from a given point, the speed of control being greater when the change in thrust is greater and vice versa, regardless of the direction of said change,

JOHN HAYS HAMMOND, Jn. GEORGE A. COLLEY. 

